Manufacturing components for vehicles such as aircraft and aerospace vehicles, ground vehicles, etc., from fiber sheets is well known. A composite part including a plurality of composite plies or sheets that are pre-impregnated with an uncured resin (i.e., prepregs) may be assembled during a layup process. During layup, several (i.e., 20, 40, or more) uncured composite plies are stacked, and then air that may be trapped between each of the several plies may be removed using a vacuum during a “debulk” process. Subsequently, the resin may be cured in an oven or an autoclave. During the curing of the resin, the component is supported on a cure tool that maintains the shape of the component while heat is applied to the component to cure the resin.
The debulking and curing of the plurality of composite plies may be performed in an autoclave. Additionally, techniques have been developed for debulking composite parts without the need for an oven or autoclave. For example, a plurality of uncured composite plies may be placed into a vacuum bag and heated to a temperature below the cure temperature. A vacuum is applied to the vacuum bag to remove air from between each adjacent ply. The debulked composite part may then be removed from the vacuum bag and processed such that it is ready to be heated to a cure temperature within an autoclave.
Debulking of components through the application of heat within a vacuum bag is convenient and cost effective for smaller parts. A relatively small heater blanket may be manufactured at reasonable cost and used to debulk smaller components. However, this approach may not be suitable for some components such as aircraft components (e.g., horizontal stabilizers) which may be manufactured as a large single seamless structure.
Accordingly, there is a need for a method and apparatus for OOA debulking of composite parts out-of-autoclave that employ relatively simple and inexpensive cure tooling. There is also a need for a method and apparatus of the type mentioned above that is well suited for processing relatively large scale parts out-of-autoclave using induction heating and smart susceptors to provide precise and uniform temperature control during the debulk process.